Cannot load native platforms tab in on-premise prouction server. v10

Following the steps to deploy my apps to the apps stores. One of the steps is to generate the mobile apps by going to the Native Platforms tab in Service Stodio. But when I click on the tab it see the progress wait animated icon for a bit and then this red error message appears:

(The connection has timed out Please check Service Center logs for more information.)

I also get an error in LifeTime when I try the deploy from test approach:

2020-05-27 13:41:07Uploading modules from Testing to Production
2020-05-27 13:41:28Unable to connect to the remote server
2020-05-27 13:41:28Deploy was aborted due to problems downloading the solution pack.

In the logs I see this error:

Unable to connect to the remote server
Environment InformationeSpaceVer: 6 (Id=904, PubId=1864, CompiledWith=10.0.1023.0)
RequestUrl: https://xxxxxxxxxxxxx/NativeAppBuilder/screenservices/NativeAppBuilder/MainFlow/NativePlatforms/DataActionGetStatus (Method: POST)
AppDomain: /LM/W3SVC/1/ROOT/NativeAppBuilder-97-132334298908714016
FilePath: C:\...\PS\running\NativeAppBuilder.01652248697\
Locale: en-US
DateFormat: dd-MM-yyyy
PID: 3508 ('w3wp', Started='8-5-2020 16:15:03', Priv=2305Mb, Virt=19759Mb)
TID: 19787
Thread Name:
.NET: 4.0.30319.42000
Unable to connect to the remote server
   at ssNativeAppBuilder.ScreenServices.NativeAppBuilder_MainFlow_NativePlatforms_ScreenModel.DataActionGetStatus(HeContext heContext, RLBuildStatusList& outParamStatus, String& outParamAppServerType)
   at ssNativeAppBuilder.ScreenServices.NativeAppBuilder_MainFlow_NativePlatforms_Controller.<DataActionGetStatus>b__e(HeContext heContext, String screenName, JObject screenModel, JObject inputParameters)
   at OutSystems.RESTService.Controllers.ScreenServicesApiController.endpoint(String input, String endpointName, String apiVersion, EndpointImplementationDelegate implementation)

I think I have missed something simple. This works fine in dev and test which are hosted servers.

The app might be having the functionality of other applications but that functionality is no longer available or is incompatible. Try to cross-check the dependencies & make sure to deploy the dependencies if any -  before this particular in prod.

There has been no changes in this app. It is the same in dev, test & prod. All I am doing for now is an upgrade to MABS 6.1. This upgrade went smoothly in dev and test. I am now trying to do it in prod.

The initial upgrade to MABS 6.1 went fine in ServiceCenter - change parameters and hit save & generate. The apps built but I got the message that I have to tag in LifeTime. That is when I started having this problem. I cannot open the Natiive Platfroms tab in ServiceStudio and I cannot deploy from test to prod via LifeTime - errors detailed above.

So I do not think that dependencies is an issue. A publish on the app from ServicceCenter runs fine.

Can it be that there is a Firewall blocking access? if so, which Firewall on which server? Or put differently, is there a map of what the accesses must be in a dev, test & LifeTime inthe cloud and prod on-premise? I have forwarded the MABS connectivity page to the techs.

Does all 3 env posses same MABS version.

Coz right after a deploy..If I remember correctly there's a  build generation.

There could be an Incompatibility of your app plugins and mabs version.

For instance, most of plugins brings up issue when it comes to having build with mabs 6+

They are all on MABS 6.1 now. As I said dev & test worked fine. The only plugin in use is the Barcode scanner plugin. 

Also I can publish the application from the publish button in ServiceCenter without any issue.